The objective of this project is to construct an atlas of the subhuman primate brain using intracerebral landmarks for precise stereotaxic procedures. X-ray ventriculography will be used for visualization of the intracerebral landmarks. We have developed the basic procedures of this technique in the cat and they have proven to be significantly better than all other methods now being used in animal stereotaxic surgery. Our pilot studies showed that this technique was very precise in the monkey as well. Thus, to make proposed method available for the wide use it is necessary to construct a stereotaxic atlas compatible with ventriculographic (intracerebral) landmarks. The publication of such an atlas will greatly enhance the reliability of experimental studies on minute functional centers regardless of their location within the primate brain. This atlas can be used also for non-invasive stereotaxy; for example, computerized tomography could be substituted for ventriculography in the future.